Inkjet printing apparatus and method of making gratings

ABSTRACT

An inkjet printing apparatus and a method of making gratings are provided. The inkjet printing apparatus comprises a base; a platform provided on the base configured to carry a substrate to be processed to linearly move in a first direction on the surface of the base; and a printhead assembly provided above the platform, wherein the printhead assembly includes a printhead support and a plurality of printheads provided on a side of the printhead support facing the platform, each of the plurality of printheads is provided with a nozzle, and the printhead assembly can move linearly in the first direction. The present invention is adaptable to using inkjet printing technology to make gratings.

TECHNICAL FIELD

Embodiments of the present invention relate to an inkjet printingapparatus and a method of making gratings.

BACKGROUND

The Stereo display has become a major trend of the display field. Thebasic principle of the stereo display is to give the stereo perceptionby binocular parallax, i.e., provide a left eye with a left-eye imageand a right eye with a right-eye image, and the two offset images areseparately present to the left and right eye within the time of durationof vision, then, a stereoscopic image having a depth will be seen afterthe brain gets the two different images.

Currently, a parallax barrier approach 3D is the most popular 3D displaytechnology, and its basic structure includes a display unit and aparallax barrier under the display unit. The parallax barrier is agrating having transmission stripes and shading stripes arrangedalternately, wherein the width of the transmission region is in a rangeof 20-70 microns, and the width of the shading region is about from tensof microns to hundreds of microns.

A grating is usually made by using photolithography or inkjet printingtechnology. When the photolithography is used to make a grating, it hasa high precision, but the process is very complex and the productionefficiency is low. Theoretically, an inkjet printing technology can beused to make a grating, that is, the shading stripes of the grating aredirectly printed on a substrate. This method is simple and can improvethe efficiency of making the grating. If the inkjet printing technologyis used to make a grating, after one shading stripe is printed, theprinthead is required to be controlled precisely to move to a center ofa next shading stripe for next printing. Thus, it requires adisplacement control apparatus with a small stepping to make the gratingbecause the distance between two adjacent shading stripes in the gratingis very small, while it is hard for a transmission in the conventionaltechnology to reach such precision, and it is very expensive even thereis such one. The inkjet printing approach is hard to be implemented.

SUMMARY

Embodiments of the present invention provide an inkjet printingapparatus and a method of making gratings. The method can use inkjetprinting technology to make high precise grating without making aapparatus with a small stepping. It reduces the cost of making gratingswith the inkjet printing technology and improves the feasibility ofmaking gratings with the inkjet printing technology.

An aspect of the present invention provides an inkjet printing apparatuscomprising:

a base;

a platform provided on the base configured to carry a substrate to beprocessed to move linearly in a first direction on a surface of thebase; and

a printhead assembly provided above the platform, wherein the printheadassembly includes a printhead support and a plurality of printheadslocated on a side of the printhead support facing the platform, theplurality of printheads are provided with corresponding nozzles thereon,and the printhead assembly can move linearly in the first direction.

Another aspect of the present invention provides a method of making agrating comprising:

operating the printhead to perform a first print for generating ashading stripe of the grating on the substrate to be processed;

operating the platform to move a first distance along a first direction,operating the printhead assembly to move a second distance along thefirst direction, operating the printhead to perform a second print forgenerating the shading stripe of the grating on the substrate to beprocessed in a direction parallel to the direction of the first printedshading stripe of the grating, wherein the difference between the firstdistance and the second distance is determined from a space between thestripes to be made; and

repeating the last step until all shading stripes of the grating areprinted.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments according to the present invention will be described indetail hereinafter in conjunction with accompanying drawings such thatthose skilled in the art would understand the present invention better,in which:

FIG. 1 is an overall structural schematic view of an inkjet printingapparatus according to an embodiment of the present invention;

FIG. 2 is a structural schematic view of a printhead assembly of theinkjet printing apparatus according to an embodiment of the presentinvention;

FIG. 3 is a structural schematic view of a platform movement assembly ofthe inkjet printing apparatus according to an embodiment of the presentinvention;

FIG. 4 is a structural schematic view of a printhead movement assemblyof the inkjet printing apparatus according to an embodiment of thepresent invention;

FIG. 5 is a schematic diagram of a specific grating stripes made byusing the method of making a grating according to an embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Technical solutions according to the embodiments of the presentinvention will be described clearly and completely as below inconjunction with the accompanying drawings of embodiments of the presentinvention. It is apparent that the described embodiments are only a partof but not all of exemplary embodiments of the present invention. Basedon the described embodiments of the present invention, various otherembodiments can be obtained by those of ordinary skill in the artwithout creative labor and those embodiments shall fall into theprotection scope of the present invention.

Unless otherwise defined, all the technical and scientific terms usedherein have the same meanings as commonly understood by one of ordinaryskill in the art to which the present invention belongs. The terms, suchas “first,” “second,” or the like, which are used in the description andthe claims of the present application, are not intended to indicate anysequence, amount or importance, but for distinguishing variouscomponents. Also, the terms, such as “a/an,” “the,” or the like, are notintended to limit the amount, but for indicating the existence of atlease one. The terms, such as “comprise/comprising,”“include/including,” or the like are intended to specify that theelements or the objects stated before these terms encompass the elementsor the objects and equivalents thereof listed after these terms, but notpreclude other elements or objects. The terms, “on,” “under,” “left,”“right,” or the like are only used to indicate relative positionrelationship, and when the position of the object which is described ischanged, the relative position relationship may be changed accordingly.

FIG. 1 is an overall structural schematic view of an inkjet printingapparatus according to an embodiment of the present invention. As shownin FIG. 1, the inkjet printing apparatus according to an embodiment ofthe present invention comprises a base 1; and a platform 2 disposed onthe base 1 for carrying a substrate 6 to be processed. The platform 2can move in a linearly in a first direction on the surface of the base1. The inkjet printing apparatus further comprises a printhead assembly3 disposed above the platform 2. The printhead assembly 3 includes aprinthead support 31 and a plurality of printheads 32 located on a sideof the printhead support 31 facing the platform 2, and each of theplurality of printheads is provided with a nozzle 33. The printheadassembly 3 can move in the first direction linearly.

According to the inkjet printing apparatus in the embodiments of thepresent invention, both the platform 2 and the printhead assembly 3 canmove along the first direction. During making a grating, the platform 3and the printhead assembly 2 are moved simultaneously, and thedifference of distances generated by moving the platform 3 and theprinthead assembly 2 in the first direction is used for ensuring thespace between two adjacent shading stripes of the grating to be made. Insuch a way, the grating with a high precision can be made without theneed of the platform 3 and the printhead assembly 2 having high movementprecision. It reduces the equipment cost of making gratings with theinkjet printing technology and improves the feasibility of makinggratings with the inkjet printing technology.

The printhead assembly 3 can have a variety of configurations. Forexample, as shown in FIG. 1, the printhead assembly 3 comprises aprinthead support 31 and a plurality of printheads 32 arranged withuniform space on a side of the printhead support 31 facing the platform2 in the first direction. Each of the plurality of printheads 32 has anozzle 33 at an end thereof facing the platform 2. The diameter of thenozzle 33 equals to the width of the shading stripes of the grating tobe made and the space between each two of the nozzles 33 is adjustable.When the printhead assembly 3 according to the embodiment as shown inFIG. 1 is used to perform grating printing, for printing differentspecifications of gratings, the space between each of the nozzles 33 isadjusted to make it adaptable to the space between the shading stripesof the grating to be made. Thus, only one set of the printhead assembly3 is needed to meet requirements of making various specifications ofgratings. The nozzle 33 can be connected with the printhead 32 invarious ways, for example, a long slot is formed at an end of theprinthead 32 facing the platform 2 in a first direction, and then thenozzle 33 is fastened on the slot through a bolt. When the adjustment isneeded, it is only required to release the bolt, and the adjustment isimplemented by sliding the nozzle 33 in the long slot. However, such anadjustable mechanism needs to be calibrated as the space between each ofthe nozzles 33 would occur a slight change after several printings areperformed, thus the printhead assembly 3 of the embodiment shown in FIG.3 is suitable for making small amount of gratings with differentspecifications.

According to above embodiment, other ways to adjust the positions of thenozzles are conceivable for those skilled in the art.

The printhead assembly 3 can be arranged as shown in FIG. 2. Theprinthead assembly 3 comprises a printhead support 31 and printheads 34located on a side of the printhead support 31 facing the platform 2. Theprinthead 34 is provided with a barrier 35 at a side facing the platform2, and a plurality of jet or spout openings 36 are arranged on thebarrier 35 with uniform space therebetween in a first direction. Thediameter of the openings 36 is equal to the width of the shading stripesof the grating to be made. When the printhead assembly 3 according tothe embodiment shown in FIG. 2 is used to perform grating printing, forprinting different specifications of gratings, the barriers 35 can beequipped with opening designs with different spaces between theopenings. For example, the barriers with openings having differentspaces therebetween are made with a molding technology. For example, theopenings 36 are formed on the barriers 35, which are adaptable to thespace between the shading stripes of the grating to be made, and it onlyneeds to mount a corresponding barrier 35 when making a grating. Suchapproach is easy to operate and can ensure the precision of the spacebetween the openings 36. However, since different specifications ofgratings require different specifications of barriers 35, the printheadassembly 3 according to the embodiment of FIG. 2 is suitable for makinga large amount of gratings having the same specification.

According to above embodiment, other ways to adjust spaces between theopenings are conceivable to those skilled in the art.

There are many ways for moving the platform 2 and the printhead assembly3, which are only needed to meet the requirement that the platform 2 andthe printhead assembly 3 can move on the plane of the platform 2 in samelinear direction. For example, the driving mode can be selected from: aguide screw and a screw nut, a belting or a linear motor, and thestructures thereof are common mechanical transmission mechanisms whichcan be implemented by those skilled in the art. Referring to FIG. 3, itshows a platform movement assembly 7 for controlling the movement of theplatform according to an embodiment. When the platform 2 is required tomove along the first direction, a guide screw is provided under theplatform 2, a screw nut 74 is fitly connected with the guide screw 73,and the guide screw is arranged in the first direction. One end of theguide screw 73 is connected with a motor 71 through a gearbox 72, andthe motor 71 is fixed on the base 1. Such structure has a low cost.

FIG. 4 shows a printhead movement assembly 8 for controlling themovement of the printhead assembly 3 according to an embodiment. Theprinthead movement assembly 8 comprises a magnetic track 81 and a thrustcoil 82. When the printhead assembly 3 is required to move along thefirst direction, it only needs to arrange the magnetic track 81 of thelinear motor along the first direction, and then connect the printheadsupport 31 of the printhead assembly 3 with the thrust coil 82 of thelinear motor. Such structure has a high transmission precision.

Further, for example, as shown in FIG. 1, it is preferable to configurean ink reservoir 4 for improving the amount of ink contained in theapparatus, saving the time of frequently filling inks and improvingproduction efficiency. The ink reservoir 4 is communicated to theprinthead 3 and continuously supplies inks to the printhead.

Further, as shown in FIG. 1, the printing system of the presentapplication can includes a positioning device 5 to accurately and easilymount the substrate to be processed. The positioning device 5 isdisposed on the printhead support 31 and used to position the relativelocation of the substrate 6 to be processed with respect to theprinthead support 31.

Embodiments of the present invention also provide a method of making agrating with the inkjet printing apparatus according to any one of aboveembodiments. The method comprises:

operating the printhead to perform a first print for generating ashading stripe of the grating on the substrate to be processed;

operating the platform 2 to move a first distance along a firstdirection, operating the printhead assembly 3 to move a second distancealong the first direction, operating the printhead to perform a secondprint for generating the shading stripe of the grating on the substrate6 to be processed in a direction parallel to the direction of the firstprinted shading stripe of the grating, wherein the difference betweenthe first distance and the second distance is determined from a spacebetween the stripes to be made; and

repeating the last step until all shading stripes of the grating areprinted.

In the method of making gratings according to the embodiments of thepresent invention, as both the platform 2 and the printhead assembly 3can move along the first direction, during making gratings, the platform3 and the printhead assembly 2 are moved simultaneously, the differenceof distances generated by moving the platform 3 and the printheadassembly 2 in the first direction is used for ensuring the space betweentwo adjacent shading stripes of the grating to be made. Thus, thegrating can be made with a high precision without the need of theplatform 3 and the printhead assembly 2 having high movement precision.It reduces the equipment cost of making gratings with the inkjetprinting technology and improves the feasibility of making gratings withthe inkjet printing technology.

For example, when the grating to be made is a grating with equallyspaced shading stripes and the space between the centers of two adjacentshading stripes of the grating to be made is W, the method of printingthe shading stripes is as followed:

adjusting an absolute value V of the difference between the firstdistance and the second distance, the number N of the nozzles and thecenter distance B between two adjacent nozzles, to allow them satisfyingthe following conditions:

both B and V are a positive integer multiple of W;

at least one of B and V are an odd multiple of W;V≦B(N−1)+W;

when B≠W, B≠V.

operating the printhead to perform a first print for generating ashading stripe of the grating on the substrate to be processed;

operating the platform 2 to move a first distance along the firstdirection, operating the printhead assembly 3 to move a second distancealong the first direction, operating the printhead to perform a secondprint for generating the shading stripe of the grating on the substrateto be processed; and

repeating the last step until all shading stripes of the grating areprinted.

When the method according to the embodiment is used to print a grating,first, the parameters V, B and N are adjusted according to the W of thegrating to be printed to allow them satisfying the above conditions. Theprinciples of above conditions are discussed below:

(1) B is a positive integer multiple of W: this condition aims to ensurethe space between the shading stripes of the grating printed by each ofthe nozzles/openings is a positive integer multiple of W during the sameprinting;

(2) V is a positive integer multiple of W: this condition aims to ensurethe space between the shading stripes of the gratings printed by thesame nozzle/opening is a positive integer multiple of W during themultiple of printings;

(3) at least one of B and V is odd multiple of W: as the space betweenthe printed adjacent shading stripes of grating(s) is even multiple of Wwhen B is even multiple of W, and if V also is even multiple of W, thespace between the shading stripes of gratings printed by the samenozzle/opening also is even multiple of W during the various printings,that is, only the shading stripes of gratings of space 2 W can beprinted, but the shading stripes of gratings of the space W cannot beprinted. Thus, this condition aims to ensure that the shading stripes ofgratings with the space W can be printed;

(4) V≦B (N−1)+W: this condition limits the minimum number ofnozzles/openings, which aims to ensure the space between the shadingstripes of gratings through many nozzles/openings performing a multipleof printings when the space between the shading stripes of gratingscannot be ensured only by V value;

(5) if B≠W, B≠V: if B≠W, B=V, if the space between the printed shadingstripes of gratings cannot equal to W no matter how many times theprintings are performed, as such, the shading stripes of the gratingswith a space W between adjacent two of them cannot be made.

As shown in FIG. 5, FIG. 5 is a schematic diagram of the shading stripesof the grating made using the above method. The stripes having samewidth represent the stripes printed in the same printing in FIG. 5. Thestripes from thick to thin (from broad to narrow) in the figurerespectively represent the first printed shading stripes of the grating,the second printed shading stripes of the grating . . . , the fifthprinted shading stripes of the grating. The shading stripes of thegrating are designed to have different width in the schematic diagramsolely for the purpose of easily distinguished. The actually printedshading stripes of the grating each have same width. In this embodiment,the parameters V, N, B and W satisfy the following relationships: V=4 W,B=5 W and N=7.

The embodiments of the present invention provide a method of makinggratings, which can make high precise gratings without making a drivingdevice having a small stepping. It reduces the equipment cost of makinggratings. This method is simple, easy to operate and can make gratingswith high efficiency.

The embodiments present invention provide an inkjet printing apparatusand a method of making gratings. As both the platform and the printheadassembly can move along the first direction, during making gratings, theplatform and the printhead assembly are moved simultaneously, thedifference of distances generated by moving the platform and theprinthead assembly in the first direction is used for ensuring the spacebetween two adjacent shading stripes of the gratings to be made. Thus,the gratings can be made with high precision without the need of theplatform and the printhead assembly having high movement precision. Itreduces the equipment cost of making gratings with the inkjet printingtechnology and improves the feasibility of making gratings with theinkjet printing technology.

The above described are only exemplary embodiments of the presentapplication, but not intended to limit the scope of the presentinvention. It is apparent that those skilled in the art can make variousmodifications and variations to the present invention without departingfrom the spirit and scope of the present invention, and it is intendedthat the present invention contains these modifications, variations andany equivalents that fall into the scope of the present invention.

What is claimed is:
 1. A method of making a grating using an inkjetprinting apparatus, the inkjet printing apparatus comprising: a base; aplatform provided on the base configured to carry a substrate to beprocessed to linearly move in a first direction on the surface of thebase; a printhead assembly provided above the platform, wherein theprinthead assembly includes a printhead support and a plurality ofprintheads provided on a side of the printhead support facing theplatform, each of the plurality of printheads is provided with a nozzle,and the printhead assembly can move linearly in the first direction; anda platform movement assembly for controlling movement of the platform,the platform movement assembly including a guide screw provided underthe platform, and a screw nut fitly connected to the guide screw,wherein the guide screw is arranged in the first direction; and one endof the guide screw is connected with a motor through a gearbox, and themotor is fixed on the base; the method comprising: operating theprinthead to perform a first print for generating a shading stripe ofthe grating on the substrate to be processed; operating the platform tomove a first distance along the first direction, operating the printheadassembly to move a second distance along the first direction, operatingthe printhead to perform a second print for generating the shadingstripe of the grating on the substrate to be processed in a directionparallel to the direction of the first printed shading stripe of thegrating, wherein a difference between the first distance and the seconddistance is determined by a space between the stripes to be made; andrepeating the last step until all shading stripes of the grating areprinted.
 2. The method of making the grating according to claim 1,further comprising: when the grating to be made is a grating withequally spaced shading stripes and the space between centers of twoadjacent shading stripes of the grating to be made is W, adjusting anabsolute value V of the difference between the first distance and thesecond distance, a number N of the nozzles, and a center distance Bbetween two adjacent nozzles, allowing them to satisfy the conditions:both B and V are a positive integer multiple of W; at least one of B andV is an odd multiple of W;V≦B(N−1)+W; and if B≠W, B≠V.
 3. The method of making the gratingaccording to claim 1, further comprising: when the grating to be made isa grating with equally spaced shading stripes and the space betweencenters of two adjacent shading stripes of the grating to be made is W,adjusting an absolute value V of the difference between the firstdistance and the second distance, a number N of the openings, and acenter distance B between two adjacent openings, allowing themsatisfying the conditions: both B and V are a positive integer multipleof W; at least one of B and V is an odd multiple of W;V≦B(N−1)−W; and if B≠W, B≠V.
 4. The method of making the gratingaccording to claim 1, wherein the plurality of printheads are arrangedwith uniform space therebetween on the side of the printhead supportfacing the platform in the first direction, the nozzle has a diameterwhich is equal to a width of a shading stripe of a grating to be made,and a space between each two of the nozzles is adjustable.
 5. The methodof making the grating according to claim 1, further comprising aprinthead movement assembly for controlling movement of the printheadassembly, wherein the printhead movement assembly is a linear motor, thelinear motor includes a magnetic track and a thrust coil disposed on themagnetic track and moved linearly along the magnetic track, the magnetictrack is arranged along the first direction, and the thrust coil isconnected with the printhead support.
 6. The method of making thegrating according to claim 1, further comprising an ink reservoir,wherein the ink reservoir is communicated with the plurality ofprintheads for supplying inks to the plurality of printheads.
 7. Themethod of making the grating according to claim 1, further comprising apositioning device, the positioning device is disposed on the printheadsupport to position the substrate to be processed and the printheadsupport.
 8. A method of making a grating using an inkjet printingapparatus, the inkjet printing apparatus comprising: a base; a platformprovided on the base configured to carry a substrate to be processed tolinearly move in a first direction on the surface of the base; aprinthead assembly provided above the platform, wherein the printheadassembly includes a printhead support and at least a printhead providedon a side of the printhead support facing the platform, the printhead isprovided with a plurality of spout openings, and the printhead assemblycan move linearly in the first direction; and a platform movementassembly for controlling movement of the platform, the platform movementassembly including a guide screw provided under the platform, and ascrew nut fitly connected to the guide screw, wherein the guide screw isarranged in the first direction; and one end of the guide screw isconnected with a motor through a gearbox, and the motor is fixed on thebase; the method comprising: operating the printhead to perform a firstprint for generating a shading stripe of the grating on the substrate tobe processed; operating the platform to move a first distance along thefirst direction, operating the printhead assembly to move a seconddistance along the first direction, operating the printhead to perform asecond print for generating the shading stripe of the grating on thesubstrate to be processed in a direction parallel to the direction ofthe first printed shading stripe of the grating, wherein a differencebetween the first distance and the second distance is determined by aspace between the stripes to be made; and repeating the last step untilall shading stripes of the grating are printed.
 9. The method of makinga grating according to claim 8, wherein the printhead is provided with abarrier at a side facing the platform, and a plurality of spout openingsare arranged with equal space therebetween on the barrier in the firstdirection, the openings has a diameter which is equal to a width of ashading stripe of a grating to be made.
 10. The method of making agrating according to claim 8, further comprising a printhead movementassembly for controlling movement of the printhead assembly, wherein theprinthead movement assembly is a linear motor, the linear motor includesa magnetic track and a thrust coil disposed on the magnetic track andmoved linearly along the magnetic track, the magnetic track is arrangedalong the first direction, and the thrust coil is connected with theprinthead support.
 11. The method of making a grating according to claim8, further comprising an ink reservoir, the ink reservoir iscommunicated with the printhead for supplying inks to the plurality ofprintheads.
 12. The method of making a grating according to claim 8,further comprising a positioning device, wherein the positioning deviceis disposed on the printhead support to position the substrate to beprocessed and the printhead support.
 13. A method of making a gratingusing an inkjet printing apparatus, the inkjet printing apparatuscomprising: a base; a platform provided on the base configured to carrya substrate to be processed to linearly move in a first direction on thesurface of the base; and a printhead assembly provided above theplatform, wherein the printhead assembly includes a printhead supportand a plurality of printheads provided on a side of the printheadsupport facing the platform, each of the plurality of printheads isprovided with a nozzle, and the printhead assembly can move linearly inthe first direction, wherein the plurality of printheads are arrangedwith uniform space therebetween on the side of the printhead supportfacing the platform in the first direction, the nozzle has a diameterwhich is equal to a width of a shading stripe of a grating to be made,and a space between each two of the nozzles is adjustable; the methodcomprising: operating the printhead to perform a first print forgenerating a shading stripe of the grating on the substrate to beprocessed; operating the platform to move a first distance along thefirst direction, operating the printhead assembly to move a seconddistance along the first direction, operating the printhead to perform asecond print for generating the shading stripe of the grating on thesubstrate to be processed in a direction parallel to the direction ofthe first printed shading stripe of the grating, wherein a differencebetween the first distance and the second distance is determined by aspace between the stripes to be made; and repeating the last step untilall shading stripes of the grating are printed.
 14. The method of makinga grating according to claim 13, further comprising a platform movementassembly for controlling movement of the platform, wherein the platformmovement assembly includes a guide screw provided under the platform, ascrew nut fitly connected to the guide screw arranged in the firstdirection, one end of the guide screw is connected with a motor througha gearbox, and the motor is fixed on the base.
 15. The method of makinga grating according to claim 13, further comprising a printhead movementassembly for controlling movement of the printhead assembly, wherein theprinthead movement assembly is a linear motor, the linear motor includesa magnetic track and a thrust coil disposed on the magnetic track andmoved linearly along the magnetic track arranged along the firstdirection, and the thrust coil is connected with the printhead support.16. The method of making a grating according to claim 13, furthercomprising an ink reservoir, wherein the ink reservoir is communicatedto the plurality of printheads for supplying inks to the plurality ofprintheads.
 17. The method of making a grating according to claim 13,further comprising a positioning device, wherein the positioning deviceis disposed on the printhead support to position the substrate to beprocessed and the printhead support.